Shunt-wound series arc-lamp.



PATENTED MAY 12j, A19.03. M. H. BAKER.. SHUNT WOUNDSBRIESARG LAMP.

APPLIOATION- FILED IA'R. 11', 1902.

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No. 727,569. PATBNTBDMAY 12, 1903.

M. H. BAKER. SHUNT WOUND SERIES ARG LAMP. APPLICATION FILED MAR. 11, 1902.

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UNITED STAT-Es Patented May 12, 1903.

PATENT OFFICE.

MALCOLM I-I. BAKER, OF EAST LIBERTY, PENNSYLVANIA, ASSIGNOR TO WESTINGI-IOUSE ELECTRIC & MANUFACTURING COMPANY, A CORPO- RATION OF PENNSYLVANIA.

SPECIFICATION forming part of Letters Patent No. 727,569, dated May 12, 1903.

Application filed Marchll, 1902. Serial No. 97,698. (No model.)

To all wtont t may concern:

Be it known that I, MALCOLM H. BAKER, a citizen of the United States, and a resident of East Liberty, in the county of Allegheny and State of Pennsylvania, have invented certain new and useful Improvements in ShuntlVound Series Arc-Lamps, of which the following is a specification.

My invention relates to improvements in shunt-type series alternating-current arclamps. Heretofore in lamps of this type the carbons have stood apart when the lamp was out of operation, being separated by the action of a spring or counterweight, and they have been brought together by the action of the current traversing and energizing a shuntmagnet when the circuit was thrown on. This construction has given rise to certain faults of operation in shunt-type lamps, such faults being, in general, great electrical strain upon the insulation and great mechanical strain upon the moving parts of the lamp. Both of these faults manifest themselves solely or mainly when the circuit is first closed. The explanation of these faults is as follows-z When the lamp is out of operation and the carbons are separated, the only closed electrical circuit through the lamp is the fine-wire winding of the shunt-magnet, which is of high inductance and resistance.

forced through the shunt-magnets for a brief' interval, the effect being to set up an abnormally high potential at the terminals of such lamps and to throw the carbons into contact with great force, straining the mechanical structure of the moving parts and endangering the insulation of the lamps. Attempts Vhen a circuit containing a number of lamps is thrown on,

results attained in the differential type of lamp, Where the path of low resistance is provided by having the carbons themselves in actual contact at the start. On the other hand,the shunt type of lamp possesses decided advantages over the differential type in that it is independent of the value of the current in the circuit and is not affected by current fluctuations. This independence is brought about by the fact that the lamp is regulated, not by a coil or magnet in which the main current is fiowing, but operates solelythrough theaction of the shunt-magnet-opposing a suitable counterbalance which may be adj usted for the proper arc voltage by varying the effective pull of thecounterbalance. When the adjustment has once been made, the relations will not be affected by changes in. the value of the main-circuit current.

The present invention combines the desirable feature of starting the lamp with the carbons in contact, as in the differential type of lamp, with the independent operating action belonging to the shunt type.

In carrying out my invention I include in the lamp a small auxiliary magnet in addition to the usual shunt magnet or magnets,the auX- iliary magnet being connected in series with the carbons. The auxiliary magnet operates an iron core of sufficient weight to overcome the normal counterbalance for the upper carbon,and thus maintains the carbons in contact before the starting of the lamp. When current is thrown on and current begins to pass through the carbons, the auxiliary magnet lifts its core, which then ceases to be controlling as against the counterbalance forthe upper carbon, permittingthe latter to be lifted, so as to establish the arc. This position of the core is maintained for all values of the current between the limits of commercial operation, and the lamp operates purely as a shunt-lamp.

In practice I connect one terminal of the IOC lamp to the upper-carbon carrier and the other lamp-terminal through the auxiliary magnet to the lower carbon. The shunt-magnet is connected directly across the carbons. To the upper-carbon tube is rigidly attached a bracket carrying a contact-point so arranged as to make contact with a cut-out plate or point when the said tube is in its lowest position. The cut-out plate or point is connected through a small resistance te the lowercarbon terminal of the lamp, thus forming a short circuit across the lamp when the cutout contacts are together'. Accordingly when the lamp is out of operation there are three possible circuits for the current to traverseiirst, through the shunt-winding; second, through the auxiliary magnet and carbons, and, third, through the cut-out circuit including the resistance. The shunt-path is of such high resistance and inductance as to take practically no current before the carbons begin to separate, and it may therefore be neglected. W'hen the circuit is closed, the current will divide between the other two paths, and as the cut-out circuit includes a resistance sufficient current will pass through the circuit including the carbons and the auxiliary magnet to energize the said magnet, lit't its core, and permit the counterbalance to separate the carbons and establish the are. It for any reason the carbons stick or fail to feed, the shunt-magnet draws the carbon-carrying tube down past the feedingpoint and brings the cut-out contacts together. This shunts out the lamp through the cut-out. resistance and denergizes'the auxiliary magnet. The core of the said magnet then falls, overcoming the action ofthe counterbalance and holding the cut-out contacts together. A Value of one ohm is found to be sufficient to give to the cut-out resistance in order to cause the lamp to pick up again should the carbone feed into contact after cutting out.

From the foregoing it is clear that at the start the current traverses two paths, both of Very low resistance and inductance. For this reason the starting voltage is practically negligible and no strain, either electrical or mechanical, is put upon the lamp. As the auxiliary magnet is of small dimensions and low resistance, there is only a slight loss of energy due to its introduction. Moreover, the core of the auxiliary magnet is arranged to float freely, and it introducesa slight Variable inductance into each lamp, which assists in steadying the main current while the operation is going on.

Another feature of my invention is a novel form of gas-check, the details of which will appear farther on. I also show and describe a novel clutch.

The details ot' my invention will be clearly understood by reference to the accompanying drawings, in which Figure 1 isa vertical section of my improved arc-lamp, showing also a diagram of the circuits. Fig. 2 is an elevation of my lamp looking from the rightin Fig. 1, and Fig. 3 is a diagram of the lamp-circuits.

In the drawings, 1 is the usual head or cap for an arc-lam p, and 2 is the usual insulatingroller, through the medium of which it may be suspended from any suitable support. From the lower side of the head or cap 1 projects a cylindrical casting 3, internally screwthreaded and adapted to receive a tube 4, constituting one of the main portions of the upper-lamp frame. Within the tube 4 a smaller tube 5 is adapted to move up and down, this tube 5 being provided with a head 6, of insulating material. The connection between the tube 5 and the head 6 may be made by crimping the upper end of the tube into an annular notch 7, formed in the head, as

shown. On the tube 5 mounted a ring or cylinder 8, of iron, constituting the core of the shunt-magnet 9. In these features there is nothing novel excepting details, and it is not thought necessary to describe them further. Within the tube 5 is mounted a carbon-carrier 10, to which is secured a wire 11, preferably wound in a spiral around the cylindrical upper end of the carbon-carrier and connected at the top to a split ring 12, bearing against the inner wali of the tube 5, so as to make good electrical connection therewith. The head 6 supports a bracket 13, through the arms of which a pin 14 passes. The pin 14 is connected by a loop 15 with a lever 16, having a depression 17, in which the upper part of the link lies. The lever 16 carries at one of its ends an adjustable weight 18 and also the cylinder 19 of a dash-pot, the piston 2O of which is supported on a piston-rod 21, pivoted at 22 to a bracket 23, secured to the tube 4. The lever 16 passes through slots 24 24 in the tube Jt and is pivoted at 25 to a bracket 26 on the said tube. At the end opposite the weight or counterbalance 18 the lever 16 passes through a slot 27 in a yoke 28, attached to the core 29 of my auxiliary magnet 30. When the lamp is not in operation, the core 29 draws the yoke 28-by gravity down upon the free end of the lever 16. Said core is so proportioned in weight as to overcome the effect ot' the weight or counterbalance 18, for which reason the tube 5 is caused to drop when the core 29 is in its downward position and to carry the carbons into contact. The parts are illustrated, however, in the position which they occupy at the moment of starting after the core has been drawn, but before the weight has operated to separate the carbons. At such times the core 29 is drawn up, so as to release the right-hand end of the lever 16 and allow the weight or counterbalance 18 to predominate, thus carrying the lever 16 upward and raising the carbon-containing tube.

The auxiliary magnet 30 is in series with the carbons, the latter being shown at 31 and 32. The circuit enters the lamp at the binding-post 33, passing by way of a wire 34E to the magnet 30, thence by way of the wire 35 or ICO IIO

verace the lamp-frame to the carbons 32 and 31, and thence through the upper carbon, its tube, and a wire 37 to the binding-post 38 for the outgoing circuit. A branch 39 from the wire 35 passes to the shunt-magnet 9 and from there by way of a wire 40 to the wire 37 and ont at the binding-post 3S. The wire 37 extends to a contact 41, mounted in a conductingbracket 42, secured by a set-screw 43 to the tube 5. In this way the wire 37 is always electrically connected with the upper carbon and its carrier through the tube 5. A branch wire 44 from the wire 34 runs to an insulated contact-terminal 45, preferably of brass, cooperating with the contact piece or terminal 41. In the wire 44 I insert a resistance 46 of about one ohm, or the wire itself may be selected to have such a resistance.

The wires 37, 44, and 34 constitute a cutout for the lamp when taken in connection with the contact-terminals 41 and 45. This cut-out cornes into play whenever the lamp is thrown out of operation, as by the sticking or breaking of one of the cai-bons. The resistance of one ohm, or thereabout, is given to the wire 44 or the resistance 46 included therein in order to permit the lamp to start undera condition of contact between the terminals 41 and 45. By virtue of such resistance in the cut-out circuit sufficient current will pass through the main-line circuit, including the carbons and the auxiliary magnet, to energize the latter and throw the carbon-carrying tube into the power of the weight or counterbalance 13, thus causing the separation of the carbons and the starting of the lamp. Then the lamp is once started, the magnet 30 being in the circuit of the carbons is kept energized and the lamp operates as an ordinary shunt-lamp.

The terminal 45 is supported within a bushing 47, preferably of vulcabeston, secured within a plate 43, of metal. The plate 4S is secured by means of posts 49 49 to the frame of the magnet 9. These posts pass down through the plate 48 and serve as a support for what may be called the lower lamp frame, the main portion of which is a plate 50, of metal. The plate 50 has a circular opening at or near its center, in which opening is held a button 5l, of lava or other good insulating heat-resisting material. The button 51 is itself hollowed out, as shown in Fig. 1, to receive washers 52 52, of steel. These washers are provided with openings for permitting the upper carbon 31 to pass through, and they are loosely placed within the opening in the button 51.

To the plate 50 is secured a single side rod 53, forming, with a bracket 54 at its lower end, a support for the lower carbon 32.

The clutch apparatus which I employ in connection with the described lamp is especially designed to prevent the noises which are common in alternating-current arc-lam ps. I accomplish this result by causing the clutch when in action 'to press the upper carbon and its carrier so that it will bind at two fixed points, the clutch itself being laterally movable, so that when it is tripped it will offer no resistance to the proper feeding of the carbon.

The clutch proper is shown at 55, the body of the clutch being of ring form and allowing the upper carbon to pass through it. One end of the clutch rests in the present instance upon the button 51, while the opposite end is of yoke form, the bridge of the yoke being adapted to slide upon the inclined surface of a head 56, attached by a bracket 58 to the lower end of the tube 5. The head 56 is formed on a post 57, mounted in the bracket 58, so as to be insulated therefrom.

With the clutch arranged as described the tendency of the clutch proper will be to press inward, say, toward the left in Fig. I, and thus cause the carbon to bear against alittle washer 59, secured to the under side of the bracket 58, while the carbon-carrier will likewise bind upon the inner wall of the tube 5, as will be seen by referring to the part 10, as illustrated in Fig. 1. In this way the carbon will be iirmly held while the lamp is burning and the usual humming noise will be prevented. On the other hand, when the clutch is tripped by its outer end coming into coutact with the button 5l with sufficient force the clutch will be easily pushed, say, toward the right iu Fig. l and allow the carbon to feed in the usual Way.

Broadly speaking, the clutch described differs from the usual ring-clutch by providing a laterally-movin g bearing instead of a iixed center of motion. In this way I secure the advantages of the ring-clutch and at the same time provide a binding effect `in addition to the usual gripping effect-that is to say, my clutch grips the carbon so as to hold itfrom all voluntary or accidental feeding and at the same time presses the carbon against the two fixed points until the proper time for further feeding supervenes.

By the use of the above-described lamp construction I secure a shunt -lamp starting smoothly with the carbons in contact and combining the good features of both the diierential and the shunt types of lamp.

I have shown and described the upper-carbon counterbalance as a weight; but it may be in the form of a spring, as will be readily understood. It will also be understood that the principles herein described are applicable to lamps of the two-magnet type-that is to say, two shunt-magnets or two auxiliary magnets, or both, having U -shaped cores may be employed.

The bowed carbon-rod 53 I generally cover in practice with porcelain or other good heatresistinginsulating material to prevent shortcircuiting.

I claim as my invention- 1. In an electric lamp, an upper-carbon carrier, means normally tending to raise the same and strike the arc, means for restraining said arc-striking means, in combination IOO with means for removing the restraining means when the lamp is operated.

2. In an electric-are lamp, a pair of carbons, a Weight acting on one of the carbons to separate it from the other, a shunt-magnet acting in opposition to the said weight, the weight and the shunt-magnetserving by their opposing actions to regulate the lamp, and an auxiliary magnet whose core or armature preponderates over said weight when the lamp is not in operation.

3. In an electric-are lamp, a pair of carbons, a counterbalance acting on one of the carbone to separate it from the other when the lamp is in operation, a shunt-magnet acting differentially in respect to the said counterbalance when the lamp is in operation, the said counterbalance and the said magnet serving as the sole forces for regulating the arc, and means for overcoming the said counterbalance when the lamp is out of operation, and for relieving the counterbalance when the lamp is operating.

4E. In an electric-arc lamp, a pair of carbons, and a counterbalanoe acting ou one of the carbons to separate it from the other, a shunt-magnet acting in opposition to the said counterbalanoe when the lamp is in operation, the magnet and the counterbalance serving by their opposing action to regulate the arc, and an auxiliary magnet in series with the carbons, the core or armature of said magnet preponderating over the said counterbalance when the lamp is out of operation and relieving said counterbalance when the lamp is in operation.

5. In an electric-arc lamp, a pair of carbons, a counterbalance connected with one of the carbons and adapted to separate it from the other carbon, when unimpeded, and an electromagnetic trip for the counterbalance, in series with the carbons.

G. In an electric-arc lamp, a longitudinally-movable carbon, a clutch coperating therewith and a beveled support for the outer end of the clutch, whereby the same is rendered laterally movable.

7. In an electric-arc lamp, a longitudinally-movable carbon, a beveled support in proximity thereto, and a clutch cooperating with the carbon near one end and resting near the other end upon the beveled surface ofthe support, whereby the clutch tends to press laterally against the carbon and whereby an easy release of the carbon for an upward movement is secured.

8. In an electric-arc lamp, a longitudinally-movable carbon and a gravity-clutch therefor, the said clutch being adapted, in moving downward, to be urged into a gradually-narrowing space, whereby a lateral pressure of the clutch against the carbon is secured.

Si. In an electric-arc lamp, a longitudinally-movable vertical carbon, a rigid clutch therefor bearing in one direction against the carbon and in the opposite direction against a wall which gradually approaches the carbon in a downwardly-inclined direction.

l0. In an electric-arc lamp, a longitudinally-movable vertical carbon, a rigid clutch therefor bearing in one direction against the carbon and in the opposite direction against a wall which gradually approaches the carbon in a downwardly-inclined direction in combination with a trip for the said clutch.

Signed at New York, in the county of New York and State of New York, this 8th day of March, A. I). 1902.

MALCOLM H. BAKER.

Witnesses:

WM. H. CAPEL, GEORGE I-I. STooKBRIDGE. 

